1. Field of the Invention
This invention directs itself to rotary internal combustion engines. In particular, this invention directs itself to a modular rotary engine wherein a combustible mixture of fuel is injected into supercharged air and ignited and expanded to rotate the engine drive shafts in successive steps by means of successively positioned rotors arranged in respective axially aligned power conversion rotor stages. More in particular, this invention pertains to rotary engines wherein the combustion air is supercharged by the same rotors which are driven by the expanding combustion gases. Further, the invention directs itself to rotors arranged in contactless meshing relationship wherein high temperature operation can be achieved through the use of ceramic material compositions.
2. Prior Art
Continuous combustion rotary engines and rotary engines in general are well known in the art. The best prior art known to the Applicant include U.S. Pat. Nos. 1,155,335; 2,246,235; 2,691,482; 3,498,184; 3,550,565; 3,640,252; 3,693,601; 3,699,930; 4,018,549; 4,068,984; 4,512,302; 4,776,779; and, 5,004,412.
Some prior art systems such as that shown in U.S. Pat. No. 3,693,601 are directed to rotary internal combustion engines comprising a plurality of rotary pumps arranged in successive communicating fashion. In such systems the stages of combustion gas expansion take place within a single cylinder and the expanded gases are thereby forced to successively enter the space between pairs of opposing rotors to cause a wedging action between the flutes, and thereby drive the respective drive shafts of each rotor set. The compression ratio for each of the sets of rotors is dependent upon the depth and width of the flutes in the cooperating rotors, with the axial length of each rotor being the same from one stage to the next. Whereas in the instant invention the expanding combustion gases are substantially prevented from such wedging action and flow tangentially with respect to the axial direction of the drive shafts within each cylinder. Thus in the instant invention the force generated by the expanding combustion gases is a function of the axial length of the rotor, with the height of the flutes being uniform throughout the engine. Further, the instant invention isolates each set of rotors in individual stages or cylinders, and through the utilization of purging rotors substantially divides the cylinder or stage into two sections, one for expansion of the combustion gases and a second portion for compression of the air to be supplied for mixing with the fuel.
In other prior art systems, such as that disclosed in U.S. Pat. No. 1,155,335 there are provided internal combustion rotary engines utilizing intermeshing rotors. Here again, the combustible fuel is carried by the spaces between the intermeshing teeth of the rotors, compressing the fuel and sequentially feeding the fuel to a combustion chamber defined between the rotors and a portion of the casing. This is volumetrically very inefficient because the very small air/fuel charge trapped between the intermeshing teeth are then expanded into a very large volume, resulting in a low horsepower output. While such systems may include purging rotors (FIG. 17), such are utilized for maximizing the intake of fresh air. These intermeshing rotors are utilized for expelling any exhaust gas which might tend to remain in the spaces between the gear teeth, and create a vacuum to aid in bringing fresh air into the engine. Whereas in the instant invention purging rotors are utilized to prevent combustion gases from passing from the expansion section of the cylinder to the compression portion, as well as preventing the compressed air from entering the expansion section.
In still other prior art systems there are known compound steam engines having had a plurality of cylinders, each cylinder having a different displacement. The high pressure steam entered the smallest displacement cylinder first, then exhausted into one or more intermediate cylinders and then to the largest cylinder before being exhausted to ambient. All of the cylinders being coupled to a common crank shaft for maximizing the utilization of the steam's energy. By exhausting the steam pressure at near ambient conditions such approaches the phenomenon called "total expansion". While this concept of maximizing the utilization of the steam's energy has been applied to turbine type power plants, such has never been known to be successfully applied to rotary pump type engines.